I was playing on a creative world and noticed sponges not clearing away water. When the sponge was removed the water did not fill the hole. After digging out an area around the water, instead of flowing into the hole the water just floated above it. This bug is probably because of the water not updating, but I don't know the actual cause. I have not seen this bug in other 1.8 worlds or 1.7.10 worlds.

(I have seen some worldgen-related floating water bug reports. This was normally generated water.)